A healthy woman normally has some vaginal discharge. Changes to that discharge may be caused by numerous health conditions or diseases, such as:

• Yeast infection. A form of vaginitis caused by an excess of the naturally occurring fungus Candida albicans. A white, cottage cheese-like vaginal discharge is the most common symptom. Certain antibiotics prescribed for infections sometimes kill the normal vaginal bacteria. This changes the balance of the vaginal flora, causing an excess of yeast. A number of other factors can also change the balance of flora, resulting in a yeast infection.
  
  
• Bacterial vaginosis (BV). A form of vaginitis caused by the Gardnerella bacteria, which is normally present in the vagina in smaller quantities. When the balance of vaginal flora changes, levels of Gardnerella bacteria may increase. BV causes a gray vaginal discharge with a fishy odor, most noticeable after sex, along with painful urination and itching.
  
  
• Pregnancy. Due to the hormonal changes that take place during pregnancy, pregnant women have increased levels of discharge that are thinner and milky white in color. They are also more susceptible to yeast infections.
  
  
• Childbirth. After giving birth, women experience vaginal discharge as their reproductive organs return to normal. Women bleed for several days after birth. Then a white or pink vaginal discharge called lochia can continue for weeks.
  
  
• Irritation. Products such as spermicides can irritate the vagina and cause discharge in some women.
  
  
• Diabetes. Variations in glucose (blood sugar) levels make women with diabetes more susceptible to yeast infections.
  
  
• Trichomoniasis. A form of vaginitis caused by the Trichomonas protozoa, usually spread through sexual contact. It may cause a greenish-yellow or gray, frothy vaginal discharge with a fishy odor.
  
  
• Sexually transmitted diseases (STDs). These may include gonorrhea, chlamydia and genital herpes. Women frequently have no symptoms at the time of STD infection, but when symptoms do occur, they may include unusual vaginal discharge. Changes can include the amount or type of discharge.

• Pelvic inflammatory disease (PID). Infection of the upper reproductive organs (often caused by gonorrhea or chlamydia). PID may not have symptoms, but when symptoms do occur, they may include unusual vaginal discharge.
  
  
• Atrophic vaginitis. A condition that may occur after menopause where decreased estrogen levels make the vagina drier and more susceptible to bleeding and infections.
  
  
• Reproductive cancers. Cancers of the uterus, cervix and other reproductive organs can sometimes cause unusual vaginal discharge.
  

Medications may also affect vaginal discharge, especially those containing hormones. The changes may not be cause for concern, and awareness of a medication’s effects can help women monitor their health during use. Medications that may change vaginal discharge include:

• Antibiotics. These medications can reduce the normally occurring vaginal bacteria. This shifts the balance of vaginal yeast and may cause the thick, white, cottage cheese-like discharge associated with a yeast infection.
  
  
• Birth control pills. Oral contraceptives contain the hormone estrogen, which normally may cause fluctuations in vaginal discharge. Birth control pills may also increase the likelihood of a yeast infection.

Conditions outside a woman’s body and her personal habits may affect vaginal discharge. Some of these factors include:

• Douching. This can change the balance of vaginal flora and allow introduction of other bacteria. Douches may also force vaginal bacteria into the uterus, which can cause an infection.
  
  
• Tight clothing. Wearing tight clothing for prolonged periods of time can create a warmer, moister vaginal environment that encourages bacterial growth and affects vaginal discharge.
  
  
• Perfumed products. Scented tampons, soaps, sprays, detergents or toilet paper may cause irritation or an allergic reaction and affect vaginal discharge.
  
  
• Poor hygiene. Improper or insufficient hygiene can introduce rectal or other outside bacteria into the vagina, especially if a woman does not wipe in a direction away from the vagina after using the toilet.
  
  
• Emotional factors (e.g., stress, sexual excitement). They can increase vaginal discharge.